Gallons Of Water On Roof

To calculate the runoff from any given rainfall.

Gallons of water on roof.

This means that each square foot captures about 62 gallons per inch of rain. In this example 600 x 240 x 1 144 000 cubic inches of water divide by 231 to get the number of gallons because 1 gallon 231 cubic inches. For every 1 inch of rain and 1 000 square feet of roof you capture about 620 gallons of water. To a depth of 1 in 1 hour.

Required roof drainage flow rate in gallons per minute 0 0104 x rainfall rate x roof area where rainfall rate is expressed in inches per hour and roof area is given in square feet. Rainwater collection calculator in gallons. 1 of rain on 1 000 sf roof will yield 623 gallons. The answer is about 623 gallons.

To find how much rain you can collect in an average rain year multiply this number by the average inches of rain. The collectable rainwater from the roof can be calculated in gallons using this calculator based on the rainfall and area. Roof area m2 x precipitation amount mm amount collected liters. Converting this to gallons per minute per square foot gpm ft 2.

If your average rainfall was 25 inches year your annual collection potential is 1 120 x 25 28 000 gallons year. Simply take your roof s square footage and multiply by 62. Take the dimensions of the footprint of your roof and convert them to inches. 1 inch of rainfall in an hour will cover 1 sq ft.

For example on a 2 000 square foot roof you can collect 2 000 x 0 56 1 120 gallons inch of rain. So a 50 x 20 roof is 600 x 240 multiply the roof dimensions by the number of inches of rainfall. How much will your roof be able to capture.